In a cell forming process of a TFT LCD, a region of a glass substrate where a frame sealant is coated needs to be irradiated with ultraviolet (UV) light, so as to cure the frame sealant. Meanwhile, in the above process, another glass substrate having a predetermined pattern needs to be used to shade the remaining region of the above glass substrate, so as to prevent a photoresist coated on the remaining region from being cured.
In the prior art, a process for manufacturing a glass substrate having a predetermined pattern includes steps of: S1: depositing an opaque metal layer on a glass substrate and coating a layer of photoresist on the opaque metal layer; S2: exposing a region of the glass substrate which corresponds to the predetermined pattern by using a mask, so as to denature the photoresist coated on the region which corresponds to the predetermined pattern; S3: developing the exposed region of the glass substrate to remove the denatured photoresist; S4: etching the glass substrate to remove portions of the opaque metal layer where the photoresist has been removed, so as to form the predetermined pattern on the glass substrate; and S5: removing the remaining photoresist on the glass substrate, so as to obtain the opaque metal layer in the region other than the predetermined pattern as a light blocking zone.
Specifically, in the above step S2, multiple exposures may be successively performed on a plurality of regions of the glass substrate to denature the photoresist on the region corresponding to the predetermined pattern through steps of: S21: shading most region of a glass substrate 2 at lower right side by using a rectangular mask 1, as shown in FIG. 1; S22: exposing the upper region and the left region of the glass substrate 2, as shown in FIG. 2; S23: moving the rectangular mask 1 (the rectangular mask 1 is moved upward as shown in FIG. 3), and a light blocking strip 3 of an exposure apparatus is used for shading desired regions of the glass substrate 2, as shown in FIG. 3; S24: exposing the unshaded region of the glass substrate 2, as shown in FIGS. 4; and S25: repeating the steps S23 and S24 to obtain the glass substrate 2 as shown in FIG. 5, and repeating the steps S23 and S24 many times to finally obtain the glass substrate 2 as shown in FIG. 6.
During the above process for manufacturing the glass substrate 2 having the predetermined pattern, the rectangular mask 1 needs to be repeatedly moved to shade a desired region of the glass substrate 2. However, in practical applications, it is difficult to move the mask exactly to the desired position. Thus, there is generally a position offset between a desired position and an actual position of the mask. The position offset will cause a region corresponding to a portion of the desired predetermined pattern not to be exposed or cause a portion of a region which should not be exposed to be exposed, resulting in a certain error between a pattern formed on the glass substrate and the desired predetermined pattern (for the glass substrate manufactured through the above-described process, the error may be a case where a distance a (as shown in FIG. 6) between two adjacent light blocking zones cannot maintain a desired value). Therefore, in practical applications, a position offset of the mask during its movement needs to be detected, so as to correct the position offset, so that a pattern formed on the glass substrate can be consistent with the desired pattern as much as possible.